Wall Street's pessimistic view of the iPhone's future continues to drag Apple stock downward, as shares of the Cupertino company opened trading below $100 for the first time in more than a year on Thursday.

RBC Capital Markets on Thursday became the latest investment firm to cut its estimates for Apple, joining the chorus of concerns that Apple could post its first-ever year over year decline in iPhone sales.

The price of of Apple stock has been driven lower by concerns over demand for the iPhone 6s lineup, dropping near $100 per share in early trading on Wednesday as investment firm Wells Fargo Securities cut its own outlook, predicting a short-term "road bump" before a return to growth.

While reporting that Apple could cut supplier orders for new iPhone 6s models by "30 percent," Japanese business newspaper Nikkei has characterized the move as "inventory adjustment" while adding that other iPhone models "have continued to sell."

Deviating from a bandwagon of media reports interpreting recent supply chain rumors as a harbinger of iPhone's first year-over-year sales contraction, PiperJaffray analyst Gene Munster believes production estimates have little to do with final reported sales. For a more accurate representation, investors should instead look to key data points from Apple itself.

Apple will reveal its quarterly financial results for the first fiscal quarter of 2016 on Jan. 26, the company said on Monday, an important three-month period that accounts for new iPhone performance and holiday sales.

Two years ago, Google made headlines when it acquired military robot maker Boston Dynamics. However, after receiving $42 million from the government to develop autonomous machine mules, the robotics group has failed to deliver anything the Marines can use and the Pentagon has ended further funding.

Despite record-breaking quarterly earnings and continued market growth in the face of withering industry headwinds, Apple stock closed out 2015 down for first time since 2008, though analysts remain positive on the company's near-future prospects.

Concerns over iPhone 6s sales continue to grow on Wall Street, as FBR & Co. became the latest firm to revise its estimates downward, calling on Apple to sell 75.5 million total iPhones in the current December quarter and cutting its price target to $150.

Apple on Tuesday issued amended corporate bylaws that affords a shareholder, or group of shareholders, with sufficient standing the opportunity to nominate a representative to the company's board of directors, a mechanism referred to as "proxy access."

Apple investors showed concern this week after iPhone supplier Dialog Semiconductor warned revenue will fall short of expectations, but Piper Jaffray took the opportunity to remind Wall Street that it's unwise to read into supplier data.

On Monday, Katy Huberty of Morgan Stanley cited channel checks and a customer intent survey as the basis for predicting the potential for iPhone sales to fall by as much as 2.9 percent over the next year, reaching a total for 2016 as low as 224 million in a "worst case scenario." The idea of "Peak iPhone" generated clickbait headlines, but the real story is that channel checks have historically been extremely worthless at predicting Apple's actual performance.